Evaluation of Occlusal Adjustment Material Removal on Monolithic Zirconia Blocks: An In Vitro Study

NCT07280130 | Not Yet Recruiting

• 1 other identifier: 202510051RINA
• Study Type: observational
• Target: 120
• Locations: 0 countries
• Sites: N/A

Brief Summary

This study aims to improve understanding of the amount of tooth-replacement material removed during a single grinding "stroke" performed in the adjustment of a zirconia crown. Zirconia is a highly durable ceramic material commonly used for dental restorations, and accurate adjustment is essential for achieving proper occlusion. However, existing literature does not provide quantitative data regarding material removal per stroke during chairside adjustment, resulting in reliance on individual clinical experience. In this study, standardized zirconia specimens will be prepared and assigned to three operator groups: dental students, dental interns, and experienced clinicians. Each participant will perform a controlled number of grinding strokes on the specimens using a commonly used dental grinding stone. Specimens will be scanned before and after grinding using a three-dimensional scanner to precisely quantify material removal. Hypothesis The hypotheses of this study are: Each grinding stroke results in a measurable and relatively consistent amount of zirconia material removal. Experienced clinicians demonstrate more controlled and predictable material removal per stroke compared with students and interns.

Conditions

Occlusal Wear of Teeth; Fixed Dental Prosthesis; Dental Occlusion

Keywords

occlusal adjustment; Monolithic zirconia; Material removal; Silicon carbide stone; 3D scan registration

Outcome Measures

Primary Outcomes (1)

• The amount of material removal per stroke

  Amount of Zirconia Material Removed per Grinding Stroke(um/stroke) * Mean thickness of material removed per stroke * Median thickness of material removed per stroke

  about 12 months

Secondary Outcomes (2)

• Change in Material Removal Rate Between Grinding Phases

  approximately 12 months

• Percentile Distribution of Zirconia Material Removal by Operator Experience Level

  approximately 12 months

Study Arms (3)

A.fourth-year dental students

Forty fourth-year dental students who have completed preclinical courses in operative dentistry, complete denture prosthodontics, and fixed prosthodontics (Part I). They have little to no experience in adjusting zirconia.

Procedure: perform material removal on monolithic zirconia

B.sixth-year interns

Forty sixth-year dental interns. Each participant will be tested twice-once before and once near the end of their clinical training. A questionnaire will also record their prosthodontic clinical experience within the past year.

Procedure: perform material removal on monolithic zirconia

C.clinicians

Forty licensed clinicians with 0-5 years of post-graduation experience (with practical experience in zirconia adjustment). A questionnaire will also document their clinical experience in prosthodontics.

Procedure: perform material removal on monolithic zirconia

Interventions

perform material removal on monolithic zirconia PROCEDURE

Each participant will perform 100 strokes along an 8-mm path at a rate of 100 strokes per minute, guided by a metronome on the monolithic zirconia

A.fourth-year dental students; B.sixth-year interns; C.clinicians

Eligibility Criteria

• Age: 20 Years - 40 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Non-Probability Sample

Study Population

The study population consists of 120 participants from three levels of dental training and early clinical practice, recruited from a dental school and affiliated clinical institutions. The sample includes: 1. Fourth-year dental students 2. Sixth-year dental interns 3. Clinicians with 0-5 years of post-graduation experience Participants are generally healthy adults capable of performing fine motor tasks required for dental procedures. Exclusion criteria include acute hand/upper-limb injuries, neuromuscular disorders, uncorrected poor vision, and inability to follow a metronome rhythm.

You may qualify if:

• Group A: Forty fourth-year dental students who have completed preclinical courses in operative dentistry, complete denture prosthodontics, and fixed prosthodontics (Part I). They have little to no experience in adjusting zirconia.
• Group B: Forty sixth-year dental interns. Each participant will be tested twice-once before and once near the end of their clinical training. A questionnaire will also record their prosthodontic clinical experience within the past year.
• Group C: Forty licensed clinicians with 0-5 years of post-graduation experience (with practical experience in zirconia adjustment). A questionnaire will also document their clinical experience in prosthodontics.

You may not qualify if:

• Acute upper-limb/hand injuries or postoperative recovery within the past 3 months that may affect grip strength or fine motor control.
• Neuromuscular disorders or tremor/postural control impairments (e.g., essential tremor, peripheral neuropathy, moderate to severe carpal tunnel syndrome) that prevent stable operation.
• Uncorrected or inadequately corrected vision that does not meet the requirements for close-range tasks (e.g., inability to clearly see fine markings at a distance of 30-40 cm even with correction).
• Inability to follow the metronome rhythm (100 beats per minute).

Sponsors & Collaborators

• National Taiwan University Hospital: lead

MeSH Terms

Conditions

Bites and Stings

Condition Hierarchy (Ancestors)

Poisoning; Chemically-Induced Disorders; Wounds and Injuries

Study Officials

• Yihao Lan, DDS, MSD

  National Taiwan University Hospital

  STUDY DIRECTOR

Central Study Contacts

Yihao Lan, DDS, MSD

CONTACT

0922901103; blue-mac@hotmail.com

Study Design

• Study Type: observational
• Observational Model: CASE CONTROL
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 1, 2025
• First Posted: December 12, 2025
• Study Start: February 1, 2026
• Primary Completion (Estimated): June 1, 2027
• Study Completion (Estimated): December 31, 2027
• Last Updated: December 30, 2025

Record last verified: 2025-12